1. Field of the Invention
The present invention relates to an optical disc recording method and an optical disc recording apparatus in which data is recorded on a recordable optical disc.
2. Description of the Related Art
Recordable optical discs, such as a CD-R, a CD+R, a DVD-R, a DVD+R, a DVD-RAM, a DVD-RW, a DVD+RW, or the like have been put to wide use in recent years. These optical discs have a guide slot known as a groove which is previously formed thereon to enable accurate tracking even in unrecorded conditions. In addition, address information is previously embedded using groove wobbling, land pre-pit, or the like to thereby enable data writing at a desired position.
Because a play-only apparatus is generally capable of tracing only a pit train, the tracing of tracks is not performed in an unrecorded region including no pit train. Further, it is also impossible to recognize the address information embedded by groove wobbling or the like, which results in inability to identify an address in the unrecorded region. Therefore, to enable reproduction by the play-only apparatus, i.e. to ensure playability of such a play-only apparatus, an optical disc needs a recorded region having a certain width.
In view of the playability, an attempt has been made up to this time where a region having at least a predetermined width is rendered as a recorded region regardless of the amount of data in each recording operation. For example, when the amount of data to be recorded is insufficient for filling the region of the predetermined width, padding data is used to fill the region.
Further, a guard zone is provided to an outer radius side of a user data area where user date is recorded, to protect an optical pickup from overrunning. On the other hand, an inner radius side of the user data area is allocated to a control data area for reproduction where information necessary for reproduction of the user data area is recorded.
FIG. 7 shows a data layout in a DVD-R. As shown in FIG. 7, a control data area A0′ to be used during data recording is formed on the innermost circumference. An outer radius side of the control data area A0′ is allocated to an inner guard zone A1′ to prevent overrun or the like. Each unit of one recording operation including a control data area for reproduction A2′ and an outer guard zone A4′ with a user data area A3′ sandwiched therebetween is sequentially recorded on an outer radius side of the inner guard zone A1′. In the direction of the radius of an optical disc, the width of the control data area for reproduction A2′ is approximately 240μm (equivalent to approximately 324 tracks), the width of the outer guard zone A4′ is approximately 500 μm (equivalent to approximately 676 tracks), and the width of the user data area A3′ is greater than or equal to approximately 1650 μm (equivalent to approximately 2230 tracks, which is the minimum recording width).
The format of such an optical disc is standardized. A data layout for a CD-R is described in Japanese Patent Laid-Open Publication No. 2001-266495.
The above-described control data area for reproduction and the outer guard zone or the padding data for filling the minimum recording width consume a recordable region of an optical disc in addition to causing an increase in length of data writing time. More specifically, even when an amount of user data equivalent to one track data is recorded, approximately 3230 tracks are used in a DVD-R while taking the length of time required for writing approximately 3230 tracks of data.